英語語法 虛擬語氣1

　　1)虛擬語氣用來表示說話人的主觀愿望或假想，所說的是一個條件，不一定是事實，或與事實相反。虛擬語氣在條件句中應用比較多。

　　2)條件句可分為兩類，一類為真實條件句，一類為非真實條件句。非真實條件句表示的是假設的或實際可能性不大的情況，故采用虛擬語氣。

　　16.1 真實條件句用于陳述語氣，假設的情況有可能發生。各種結構參見下表：

　　句 型 條件從句 主句

　　一般現在時 shall/will + 動詞原形

　　祈使句

　　情態動詞一般現在時

　　例如：If he comes, he will bring his violin. 如果他來，會帶小提琴來的。

　　典型例題

　　The volleyball match will be put off if it ___.

　　A.　will rain　 B. rains　 C. rained　 D. is rained

　　答案B。真實條件句主句為將來時，從句用一般現在時。

　　注意：

　　1)在真實條件句中，主句不能用be going to表示將來，該用shall, will.

　　(錯) If you leave now, you are never going to regret it.

　　(對) If you leave now, you will never regret it.

　　2)表示真理時，主句謂語動詞不用shall (will) +動詞原形，而直接用一般現在時的動詞形式。

　　16.2 非真實條件句

　　1)虛擬語氣可以表示過去，現在和將來的情況，時態的基本特點是時態往后推移。

　　a. 與現在事實相反的假設

　　條件從句 主句

　　一般過去時(be用were) should(would)等 +動詞原形

　　例如：If they were here, they would help you. 如果他們在這兒，會幫助你的。

　　含義：They are not here, they cant help you.

　　b. 與過去事實相反的假設

　　條件從句 主句

　　過去完成時 should(would)等+ have+ 過去分詞

　　例如：If he had come yesterday, I should / would have told him about it.如果他昨天來的話，我會把這件事告訴他的。

　　含義：He did not come yesterday, so I did not tell him about it.

　　c. 表示對將來不大可能發生的事情的假想

　　條件從句 主句

　　一般過去時 should/would等 + 動詞原形

　　were+ 不定式

　　should+ 動詞原形

　　例如：If you succeeded, everything would be all right. 如果你將來成功了，一切都會好的。

　　If you should succeed, everything would be all right.

　　If you were to succeed, everything would be all right.

　　含義：You are not likely to succeed, everything will be what it is now.

　　16.3 混合條件句

　　有時，主句與從句的動作發生在不同的時間，主句從句謂語動詞的虛擬語氣形式因時間不同而不同，這種條件句叫做混合條件句。例如：

　　If you had asked him yesterday, you would know what to do now. 如果你昨天問過他，今天就知道做什么了。

　　(從句與過去事實相反，主句與現在事實相反。)

　　If it had rained last night(過去), it would be very cold today (現在).如果昨晚下過雨，今天就會很冷了。

　　16.4 虛擬條件句的倒裝

　　虛擬條件句的從句部分含有were, should, 或had時, 可省略if，再把were, should或had 移到從句的句首，實行倒裝。例如：

　　Were they here now, they could help us. =If they were here now, they could help us.他們現在在的話，就會幫助我們了。

　　Had you come earlier, you would have met him. =If you had come earlier, you would have met him.你來得早一點，就碰到他了。

　　Should it rain, the crops would be saved. =Were it to rain, the crops would be saved.假如下雨，莊稼就有救了。

　　注意：在虛擬語氣的從句中，動詞的過去時態一律用were，不用was，即在從句中be用were代替。例如：

　　If I were you, I would go to look for him. 如果我是你，就會去找他。

　　If he were here, everything would be all right. 如果他在這兒，一切都會好的。

　　典型例題

　　_____ to do the work, I should do it some other day.

　　A. If were I　　 B. I were　C. Were I　D. Was I

　　答案C. 在虛擬條件狀語中如果有were, should, had這三個詞，通常將if省略，主語提前, 變成 were, should, had +主語的形式。但要注意，在虛擬條件狀語從句中，省略連詞的倒裝形式的句首不能用動詞的縮略形式。如我們可說 Were I not to do, 而不能說 Werent I to do。

　　1)虛擬語氣用來表示說話人的主觀愿望或假想，所說的是一個條件，不一定是事實，或與事實相反。虛擬語氣在條件句中應用比較多。

　　2)條件句可分為兩類，一類為真實條件句，一類為非真實條件句。非真實條件句表示的是假設的或實際可能性不大的情況，故采用虛擬語氣。

　　16.1 真實條件句用于陳述語氣，假設的情況有可能發生。各種結構參見下表：

　　句 型 條件從句 主句

　　一般現在時 shall/will + 動詞原形

　　祈使句

　　情態動詞一般現在時

　　例如：If he comes, he will bring his violin. 如果他來，會帶小提琴來的。

　　典型例題

　　The volleyball match will be put off if it ___.

　　A.　will rain　 B. rains　 C. rained　 D. is rained

　　答案B。真實條件句主句為將來時，從句用一般現在時。

　　注意：

　　1)在真實條件句中，主句不能用be going to表示將來，該用shall, will.

　　(錯) If you leave now, you are never going to regret it.

　　(對) If you leave now, you will never regret it.

　　2)表示真理時，主句謂語動詞不用shall (will) +動詞原形，而直接用一般現在時的動詞形式。

　　16.2 非真實條件句

　　1)虛擬語氣可以表示過去，現在和將來的情況，時態的基本特點是時態往后推移。

　　a. 與現在事實相反的假設

　　條件從句 主句

　　一般過去時(be用were) should(would)等 +動詞原形

　　例如：If they were here, they would help you. 如果他們在這兒，會幫助你的。

　　含義：They are not here, they cant help you.

　　b. 與過去事實相反的假設

　　條件從句 主句

　　過去完成時 should(would)等+ have+ 過去分詞

　　例如：If he had come yesterday, I should / would have told him about it.如果他昨天來的話，我會把這件事告訴他的。

　　含義：He did not come yesterday, so I did not tell him about it.

　　c. 表示對將來不大可能發生的事情的假想

　　條件從句 主句

　　一般過去時 should/would等 + 動詞原形

　　were+ 不定式

　　should+ 動詞原形

　　例如：If you succeeded, everything would be all right. 如果你將來成功了，一切都會好的。

　　If you should succeed, everything would be all right.

　　If you were to succeed, everything would be all right.

　　含義：You are not likely to succeed, everything will be what it is now.

　　16.3 混合條件句

　　有時，主句與從句的動作發生在不同的時間，主句從句謂語動詞的虛擬語氣形式因時間不同而不同，這種條件句叫做混合條件句。例如：

　　If you had asked him yesterday, you would know what to do now. 如果你昨天問過他，今天就知道做什么了。

　　(從句與過去事實相反，主句與現在事實相反。)

　　If it had rained last night(過去), it would be very cold today (現在).如果昨晚下過雨，今天就會很冷了。

　　16.4 虛擬條件句的倒裝

　　虛擬條件句的從句部分含有were, should, 或had時, 可省略if，再把were, should或had 移到從句的句首，實行倒裝。例如：

　　Were they here now, they could help us. =If they were here now, they could help us.他們現在在的話，就會幫助我們了。

　　Had you come earlier, you would have met him. =If you had come earlier, you would have met him.你來得早一點，就碰到他了。

　　Should it rain, the crops would be saved. =Were it to rain, the crops would be saved.假如下雨，莊稼就有救了。

　　注意：在虛擬語氣的從句中，動詞的過去時態一律用were，不用was，即在從句中be用were代替。例如：

　　If I were you, I would go to look for him. 如果我是你，就會去找他。

　　If he were here, everything would be all right. 如果他在這兒，一切都會好的。

　　典型例題

　　_____ to do the work, I should do it some other day.

　　A. If were I　　 B. I were　C. Were I　D. Was I

　　答案C. 在虛擬條件狀語中如果有were, should, had這三個詞，通常將if省略，主語提前, 變成 were, should, had +主語的形式。但要注意，在虛擬條件狀語從句中，省略連詞的倒裝形式的句首不能用動詞的縮略形式。如我們可說 Were I not to do, 而不能說 Werent I to do。